Injection of chemicals for in situ treatment of groundwater is commonly utilized to remediate regions of contamination below ground. Prior techniques for groundwater treatment of organic chemicals including chlorinated solvents and petroleum products include above-ground treatment or in situ injection of treatment materials. Typical treatment materials include neutralizing agents, steam, oxygenated solutions, biologically active materials, reducing metals, and/or mixtures of adsorbing materials along with any of the preceding treatment materials. Limitations of the use of the preceding treatment materials are many, including poor treatment efficiency, an inability to treat organic mixtures, metals and radioactive waste, high costs of materials and continuing injection of materials, production of toxic by-products, limits as to the depth of injection of materials, the dissolution of materials during injection, and the lack of dispersion of materials in situ. There is great interest in development of an injectable treatment material which will reach in situ strata of contamination without dissolution, will disperse throughout the zone of contaminated soil and groundwater, will continuously react with organic contaminants without producing toxic by-products in situ, and will bind and immobilize metals and radioactive contaminants in situ to limit the spread of toxic or radioactive contaminants in groundwater.
In Abdul et al., U.S. Pat. No. 5,690,173, incorporated herein by reference, an apparatus for enhanced bioremediation of underground contaminants is disclosed which is used within an injection well to enhance the biological treatment of water-borne soil contaminants in situ with microbes by achieving optimal levels of oxidizing agents within the soil.
In Hunt et al., U.S. Pat. No. 5,733,067, incorporated herein by reference, a treatment system is disclosed using chemically or biologically reactive sheets placed within the soil.
In Cherry et al., U.S. Pat. No. 5,641,020, incorporated herein by reference, a treatment system is disclosed for injecting hydrofracture fluid and reactive treatment material into subsurface fractures containing, or near to, contaminated groundwater, with the reactive treatment material causing contaminants to diffuse out of the soil matrix toward the fractures containing injected reactive materials, with chemical breakdown of contaminants when the contaminants come in contact with the injected reactive materials.
In Fernando et al., U.S. Pat. Nos. 5,616,253, and 5,611,936, both of which are incorporated herein by reference, various methods are disclosed for utilizing a palladized iron bimetallic system for the dechlorination of chlorinated organic compounds in contaminated soils and various effluents.
In Sivavec, U.S. Pat. No. 5,447,639, incorporated herein by reference a method is disclosed for remediation of aqueous solutions of chlorinated aliphatic hydrocarbons utilizing in situ or ex situ reactions with ferrous sulfide.
In Gillham, U.S. Pat. No. 5,266,213, incorporated herein by reference, a method is disclosed for remediation of aqueous halogenated organic compounds utilizing iron metal placed in a trench or well to produce reducing conditions.
In Billings et al., U.S. Pat. No. 5,221,159, incorporated herein by reference, a method and apparatus are disclosed for removing contaminants from soil utilizing injection wells, oxygenated gas injection, and a vacuum applied at an extraction well.
In Hard et al., U.S. Pat. No. 3,708,206, incorporated herein by reference, a process is disclosed for leaching base elements from ore deposits such as uranium from an underground water containing oxidizable materials such as sulfides and carbon utilizing oxygen bearing gas.
The above described methods utilize one or more degradative components that are injected into contaminated groundwater for remediation of contaminants or containment of contaminants. Conventional methods require pumping of large volumes of groundwater for treatment of contaminants above ground, or require injection of components that have poor treatment efficiency and require long treatment periods. Conventional groundwater treatment techniques have the drawbacks of high costs, produce toxic by-products, are limited as to the type and concentration of contaminants treated, the depth of injection of components, and/or have components that dissipate and dilute after injection, or do not disperse in situ unless pumping is continued. Continuous pumping of groundwater, or injection of short-lived components into groundwater is costly and inefficient. Thus there exists room for improvement within the art.